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QveST [7]
2 years ago
6

..............................................

Chemistry
1 answer:
Vilka [71]2 years ago
6 0
The period is the end of the sentence!!!
You might be interested in
If i have 340mL of a 1.5 M NaBr solution, What will the concentration be for 1000mL?
Gekata [30.6K]

Answer:

0.51M

Explanation:

Given parameters:

Initial volume of NaBr = 340mL

Initial molarity  = 1.5M

Final volume  = 1000mL

Unknown:

Final molarity = ?

Solution;

This is a dilution problem whereas the concentration of a compound changes from one to another.

In this kind of problem, we must establish that the number of moles still remains the same.

    number of moles initially before diluting = number of moles after dilution

Number of moles  = Molarity x volume

Let us find the number of moles;

          Number of moles  = initial volume x initial molarity

Convert mL to dm³;

                  1000mL  = 1dm³

                     340mL gives \frac{340}{1000}   = 0.34dm³

Number of moles  = initial volume x initial molarity  = 0.34 x 1.5 = 0.51moles

Now to find the new molarity/concentration;

               Final molarity  = \frac{number of moles}{Volume}    = \frac{0.51}{1}    = 0.51M

We can see a massive drop in molarity this is due to dilution of the initial concentration.

6 0
3 years ago
A reading shows a pressure measurement of 43 in. Hg. What is the equivalent pressure in psi? A. 5.73 psi B. 2223.13 psi C. 26.32
oksian1 [2.3K]
43 inHg = 43 inHg*2.54cm/in = 109.22cmHg * 10 mm/cm = 1092.2 mmHg


14.7 psi = 760 mmHg

1092.2mmHg * 14.7psi / 760 mmHg = 21.13 psi

Answer: option D. 21.13 psi
7 0
3 years ago
Read 2 more answers
HELP PLSSSSSSSSSSSSSSSSSSSSSSSSSSSSS AND PLS DO NOT JUST GUESS
astraxan [27]
Could you show the characteristics?
3 0
2 years ago
A piece of wood burns to form ash. ____C_____ Water evaporates into steam. ____P_____ A piece of cork is cut in half. ____P_____
IceJOKER [234]

Answer:

A piece of wood burns to form ash - Chemical change

Water evaporates into steam - Physical change

A piece of cork is cut in half. __ Physical change

A bicycle chain rusts. _____Chemical change

Food is digested in the stomach. _____Chemical change

Water is absorbed by a paper towel. _____Physical change

Hydrochloric Acid reacts with zinc. _____Chemical change

A piece of an apple rots on the ground. ____Chemical change

A tire is inflated with air - Physical change

A Plant turns sunlight, CO2, and water into sugar and oxygen. _Chemical change

Sugar dissolves in water - Physical change

Eggs turn into an omelet. _____Chemical change

Milk sours. Chemical change

A popsicle melts. _____Physical change

Turning brownie mix into brownies. Chemical change

Explanation:

Matter undergoes two types of changes: physical changes and chemical changes.

A physical change is one that affects only the physical properties of a substance such as colour, size, shape, etc., and in which no new substances are formed. Physical changes are easily reversible.

Chemical changes are changes which affect the chemical characteristics and properties of a substance such as reactivity, acidity, basicity, etc., resulting in the formation of new substances.

The following changes below are categorized as either physical or chemical changes based on which of the properties of the substance is affected and whether new substances result or not.

A piece of wood burns to form ash - Chemical change

Water evaporates into steam - Physical change

A piece of cork is cut in half. __ Physical change

A bicycle chain rusts. _____Chemical change

Food is digested in the stomach. _____Chemical change

Water is absorbed by a paper towel. _____Physical change

Hydrochloric Acid reacts with zinc. _____Chemical change

A piece of an apple rots on the ground. ____Chemical change

A tire is inflated with air - Physical change

A Plant turns sunlight, CO2, and water into sugar and oxygen. _Chemical change

Sugar dissolves in water - Physical change

Eggs turn into an omelet. _ Chemical change

Milk sours - Chemical change

A popsicle melts. _____Physical change

Turning brownie mix into brownies - Chemical change

3 0
2 years ago
Can anyone help me on this please?
Bad White [126]
This question is testing to see how well you understand the "half-life" of radioactive elements, and how well you can manipulate and dance around them.  This is not an easy question.

The idea is that the "half-life" is a certain amount of time.  It's the time it takes for 'half' of the atoms in any sample of that particular unstable element to 'decay' ... their nuclei die, fall apart, and turn into nuclei of other elements.

Look over the table.  There are 4,500 atoms of this radioactive substance when the time is 12,000 seconds, and there are 2,250 atoms of it left when the time is ' y ' seconds.  Gosh ... 2,250 is exactly half of 4,500 !  So the length of time from 12,000 seconds until ' y ' is the half life of this substance !  But how can we find the length of the half-life ? ? ?

Maybe we can figure it out from other information in the table !

Here's what I found:

Do you see the time when there were 3,600 atoms of it ? 
That's 20,000 seconds.

... After one half-life, there were 1,800 atoms left.
... After another half-life, there were 900 atoms left.
... After another half-life, there were 450 atoms left. 

==>  450 is in the table !  That's at 95,000 seconds.

So the length of time from 20,000 seconds until 95,000 seconds
is three half-lifes.

The length of time is (95,000 - 20,000) = 75,000 sec

                                     3 half lifes = 75,000 sec

Divide each side by 3 :   1 half life = 25,000 seconds

There it is !  THAT's the number we need.  We can answer the question now.

==> 2,250 atoms is half of 4,500 atoms.

==> ' y ' is one half-life later than 12,000 seconds

==> ' y ' = 12,000 + 25,000

         y   = 37,000 seconds  .

Check: 
Look how nicely 37,000sec fits in between 20,000 and 60,000 in the table.

As I said earlier, this is not the simplest half-life problem I've seen.
You really have to know what you're doing on this one.  You can't
bluff through it.


7 0
3 years ago
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